CO AND IRAS DETECTION OF AN INTERMEDIATE-VELOCITY CLOUD

In the course of a radio CO survey of high Galactic latitude clouds, we detected CO emission at the position l = 210°.8 and b = 63°.1 with an LSR velocity of - 39 km s-1. This molecular cloud constitutes the third one with an unusually large absolute velocity at these latitudes, as compared with the 5.4 km s-1 cloud-to-cloud velocity dispersion of the high-latitude molecular clouds. The position is coincident with an H I intermediate-velocity cloud: (GHL 11, Verschuur H, OLM 268), and an infrared-excess cloud 306 in the list by Désert, Bazell, and Boulanger (i.e., it shows more infrared emission than can be accounted for by the H I gas alone). This cloud is clearly detected at all four IRAS wavelengths and has warmer colors than the local interstellar medium. It shows evidence for grain processing because of spatial variations of the IR colors. It may be part of the supernova remnant that has been hypothesized to explain some high-latitude IVCs or may belong to family of comet-like clouds found by Odenwald. We therefore propose the existence of a new population of molecular clouds, the ones at intermediate H I velocities and high latitudes, which to date contains three known members.